1. Field of the Invention
The present invention relates to a process for the encapsulation of aspirin with a cellulose derivative. More particularly, the invention relates to a process of encapsulating aspirin in which water containing an organic solvent partially miscible with water and/or a small amount of aspirin is used as the encapsulation medium.
2. Description of the Prior Art
Processes of producing cellulose capsules containing aspirin are known. For example, there is known a method utilizing the phase separation of ethyl cellulose and polyethylene by heating and cooling it in a pure organic solvent such as cyclohexane. Such a method is accompanied by the danger caused by the requirement to heat cyclohexane to temperatures near its boiling point during phase separation, and the necessity for a complicated operation of separating polyethylene by filtration.
There is also known a process of producing such capsules utilizing the phase separation of a concentrated aqueous salt solution and acetone. However, in this process salt adhered to the walls of the capsules formed must be washed away with water, an additional troublesome operation.
These are, accordingly, technical problems which should be solved in encapsulation techniques for aspirin.